Fire sprinklers are widely used in all kinds of buildings, including hotels, hospitals, shopping malls, and schools. Current fire sprinklers incorporate a plastic tube filled with a liquid that seals a passage in the sprinkler, precluding water flow from a pressurized water supply line through the sprinkler. When the plastic tube heats up, such as in the event of a fire, the liquid within the tube boils and generates a high vapor pressure, breaking the plastic tube and allowing fluid flow through the sprinkler. Once the tube is broken, the only way to stop water from spraying from the sprinkler is to cut off the water supply to the sprinkler, such as by closing a valve upstream of the sprinkler. Even if a fire is quickly extinguished, continued operation of water sprinklers may continue to damage the space in which the fire erupted.
U.S. Pat. No. 4,590,999 discloses embodiments of a magnetically operated fire sprinkler with a sealing device that loses its magnetism at a predetermined high temperature, opening the sprinkler and allowing water flow therethrough. The sealing device, however, loses a substantial amount of its magnetism upon returning to ambient temperature or, even without a high temperature event, over time, which may lead to leaks or may require replacement of the magnets after a fire event.
There exists a need to develop a water sprinkler and/or valve that operates in response to high temperatures generated by a fire, yet automatically shuts off water flow in response to a lower temperature, such as after the fire is extinguished, which operates magnetically and which comprises a magnetic switch which is permanently operable such that the parts of which do not need to be periodically replaced.